Revolution counter



Mach 16, 1937.'I R. G. MOODY www REVOLUTION COUNTER Filed Ooi. 2, 1933ATTORNEY Patented Mar. 16, 1937 gaat@ PATE reis

REVOLUTION COUNTER Ralph G. Moody,

United States Navy Application October 2, 1933, Serial N0. 691,979

4 Claims.

(Granted under the act of March 3, 1883, as

amended April 30,

This invention relates to a mechanism for counting the revolutions ofrotating elements, such as shafts, and has for its object to provide asimple yet accurate means that will be of low cost, easy to manufactureand install, and unlikely to get out of order.

In the drawing:

Fig. 1 shows a side elevation of my invention with parts cut away, and aschematic diagram of the electrical connections therefor;

Fig. 2 is a diametral section through the rotating parts of the countermechanism.

'Ihe shaft 3 is mounted to be rotatable and is connected, preferablythrough suitable reducing l5 gears, to the element whereof therevolutions are to be counted. Within a housing t a disk 5 is mountedupon shaft 3 and is driven by the shaft through a key 6, a keyway 'Ibeing provided in the hub of disk 5 to permit longitudinal sliding ofthe disk 5 upon shaft 3. This disk has a laterally turned peripheralflange 8 whereof the edge is provided with teeth 9 adapted to engageteeth I0 on the edge of a like flange Ii on disk I2 that is freelyrotatable on sleeve I3 carried by housing 4. A spring I4 is disposedbetween disks 5 and I2 and normally keeps them separated so that shaft 3may rotate without driving disk I2. It is to be understood that shaft 3may be provided with a clutch or other suitable mechanism fordisconnecting it from the rotating element. A helical spring I5 has oneend secured to the sleeve I3 and the other end to a pin I5 fixed to diskI2 and is so wound that it tends to impart to the disk I2 rotation in adirection opposite to that of shaft 3.

A drum Il has an annular flange I8 that fits within a flange I9 on thehousing i, the periphery of drum Il having inscribed thereonrevolutionindicating numerals 2S that are visible through a window 2| inhousing 4. The coacting flanges I8 and I9 constitute the means forsupporting drum Il to permit rotation thereof. A plane helical spring 22has one end secured to sleeve i3 and the other to the flange i8 and isso wound that it tends to move the drum in a direction opposite to therotation of shaft 3. A plurality of clips 2S secured to the housing tcoact with a radially extending Iiange 24 on drum ll to prevent lateraldisplacement of the drum. Lug 25 on disk I2 is disposed to contact a lug2% on drum ll and so to form a positive driving connection between thedisk and the drum when the disk is rotated in one direction, but toleave the drum free of the disk when the disk is rotated in the oppositedirection.

Upon the periphery of iiange 24 are ratchet teeth 2'! so directed as topermit rotation of the drum in the same direction as shaft 3, but toengage the bell crank pawl 28 and prevent rotation thereoi in theopposite direction, the spring 29 being provided to hold the pawl inposition to engage teeth 21. A solenoid 30 is disposed to rock pawl 28on its pivot and disengage it from teeth 2l at certain times as will behereinafter set forth. A bell crank lever 55 is pivotally mounted withone arm disposed to be movable against the member 3l and push disk 5over so the teeth S thereof engage the teeth l0 of disk l2, a solenoid32 serving to rock the lever 5t and so move disk 5 as mentioned.

The clock mechanism diagrammatically represented by gears 33 drives thecontact arm 3A at a predetermined speed. The contacting element 35 onarm 3d bridges the arcuate contact segments 3S and 3l and connects themtogether electrically, the said segments being in circuit with` thesolenoid 32. A second pair of contact segments 33 and 39 are connectedtogether by the contacting element IB on arm Sii. It is to be noted thatthe segments 36 and 3l have an angular extent oi` substantially 270while the segments 38 and 39 are about and that the arm 3d will move ofithe last-mentioned segments before it does olf the first-mentionedsegments.

The mode of operation is as follows: It is assumed that the shaft 3 isconnected to the element whereof the revolutions are to be counted andthat arm Sli is being driven by the mechanism 33. As soon as elementcomes in contact with the segments Se and 3l, the direction of rotationof the arm being indicated by the arrow, solenoid 32 will be energizedand will rock the lever 5t which will slide disk 5 into drivingengagement with disk l2. Through lugs 25 and 25 the drum Il will berotated by disk i2 and will continue to rotate until arm 34 has passedcompletely over the segments 56 and 3l. As soon as arm Sti passes osegments 3G and 3'?, the solenoid 32 will be de-energized and spring Itwill disengage disk 5 from disk i2, whereupon the spring I5 will rotatedisk i2 back to its initial position. The drum il, however, will be heldagainst reverse movement by pawl 26 and may be read through the window2.

It is to be noted that during the rst revolution of arm @t the solenoidSil will be energized during the time that element le bridges thesegments 38 and Se, but this bridging of segments 38 and 39 will have noeffect since the drum is being positively driven by disk l2. However,during the next and subsequent revolutions of arm 34, as soon as elementd!) bridges segments 38 and 39, pawl 28 will be released from teeth 2land spring 22 will move drum Il back until the lug 2E on the drum meetslug 25 on disk i2 after which the drum will move forwardly with disk l2until the disk again ceases to rotate. If the shaft 3 has slowed down itis apparent that the drum will not be driven as far around as it- Wasthe previous time and the reading will be lower; on the contrary, ifshaft 3 has speeded up, the disk will be carried beyond its previousposition before being stopped and the reading will be higher. Breakingthe circuit through segments 38, 39 and solenoid 3U before the drivingof disk I2 is terminated through interrupting the circuit that includessegments 36 and 31, insures that pawl 28 will be operative to lock drumIl in the position it has when the disks disengage and so holds the drumstationary at its maximum reading.

A stop il is provided to engage a lug 42 on disk l2 and arrest thereverse movement of the disk at the proper place. If desired, lugs 25and 2S may have their contacting faces coated with some substance of lowelasticity, such as lead, wood or rubber, or they may have blocks ofsuch material set into them, to prevent excessive rebound and shock whenthe drum moves back into driving engagement with the disk. The rate ofrevolution of arm 3ft should, with the construction shown, be soadjusted to the rate of shaft 3 that the disk l2 will not be driven afull revolution during one timing interval at the maximum speed of therotating element to which the device is connected. If disk i2 should bedriven more than one revolution there would be danger of breaking springl5. The numerals 2e on drum Il' should be continuous from one to themaximum number of revolutions p er unit time executed by the rotatingelement to which shaft 3 is connected. A convenient time interval forone revolution of arm 3d is four seconds, which will give at least onesecond out of each four during which the drum Il will be stationary andcan be easily read.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmentalpurposes, without the payment of any royalties thereon.

I claim:

1. A revolution counter, comprising a shaft drivable at a rate havingknown relation to the rate of the shaft whereof the revolutions are tobe counted, a first disk mounted thereon to rotate therewith but to beslidable longitudinally thereof, said disk having a laterally turnedperipheral flange with teeth on the edge thereof, a second diskrotatably mounted on said shaft, said second disk having a laterallyturned peripheral flange with teeth engageable with the teeth on thefirst disk and a laterally projecting lug on the side thereof oppositesaid flange, a spring between said disks tending to separate them, aplane helical spring connected to said second disk to move it in thedirection opposite to the rotation of the rst disk; a rotatable drumhaving revolution indicatirrI marks on its periphery, ratchet teeth onthe periphery of the drum so directed as to permit rotation thereof inthe direction of rotation of said shaft and having a lug engageable bythe lug on said secn ond disk; a plane helical spring connected tosaiddrum to rotate it in the direction opposite to the rotation of saidshaft, means to engage said ratchet teeth to lock said drum againstbeing rotated by said helical spring, means to move said first diskperiodically into engagement with said second disk for a predeterminedinterval, and means to release said locking means during each period ofengagement of said disks, said interval of release of the locking meansbeing much less than the said period of engagement and terminatingshortly before the termination of said engagement.

2. A revolution counter, comprising a rotatable shaft, a first diskfeathered thereon to slide longitudinally thereof, a second diskrotatably mounted on said shaft, said disks having interengageableportions, a lug on said second disk extending oppositely to the saidinterengaging portion thereon, a spring between said disks tending toseparate them, means normally tending to move said second disk oppositeto the direction of rotation of said shaft; a rotatable drum c0- axialwith said disks having revolution indicating marks on its periphery,ratchet teeth on its periphery so directed as to permit rotation thereofin the direction of rotation of said shaft and having Aa lug engageablewith the lug on j said second disk, means to rotate the drum in thedirection opposite to the rotation of said shaft, means normally lookingsaid drum against rotation in said opposite direction, a firstelectrically actuatable means to release said locking means, means toslide said first disk longitudinally of said shaft into engagement withsaid second disk, a second electrically actuatable means to operate thelast previously mentioned means, and

time-controlled means to govern the energization of both of saidelectrically actuatable means, the time of actuation of the secondelectrically actuatable means beginning much earlier and ending somewhatlater than the time of actuation 0f the lrst electrically actuatablemeans.

3. A revolution counter, comprising a rotatable member having on itindicia, means to rotate said member in one direction, means to locksaid member against movement in the opposite direction, means tending tomove said member in said l opposite direction; means to control therotation of said member in said one direction including a solenoid, apair of spaced concentric conducting members respectively connected tothe terminals of said solenoid, a rotatable arm pivotally mounted at thecenter of curvature of said conducting members, a conducting element onsaid arm contactable with said conducting members to close the circuitthrough said solenoid, horological means to drive said arm; a secondpair of spaced conducting members concentric with each other and withthe aforesaid pair, a second conducting element on said arm to Contactthe members of said second pair, and a solenoid having its terminalsrespectively connected to the members of said second pair and disposedto unlock said locking means when energized, the angular extent of saidsecond pair being small in comparison with that of the first pair andthe termini of said second pair being disposed to be reached by said armbefore those of the rst pair.

4. A revolution counter, comprising a rotatable shaft, an indicatingdrum rotatable thereon and provided with ratchet teeth on its periphery,means to drive said drum including a member rotatable with said shaftbut slidable longitudinally thereon, a bell-crank pawl mounted to haveone end engageable with said ratchet teeth, a spring to hold said end incontact with said ratchet teeth, a iirst solenoid to move said pawl outof engagement with said ratchet teeth, a bellcrank lever having one armdisposed to be movable against said member to slide said member andthereby effect a driving connection between said member and said drum, asecond solenoid disposed to act on the other arm of said lever so tomove said one arm, a pair of concentric contact elements in the form ofa major circular segment respectively connected to the terminals of saidsecond solenoid, another pair of contact elements in the form of a minorcircular segment adjacent the first mentioned segments but terminatingshort of the termini of the first said segments respectively connectedto the terminals of the iirst solenoid, a rotatable arm mounted at thecommon center of all of said segments and having a circuitclosingcontact element electrically connecting together the elements of thefirst said pair and a like element to connect together the elements ofsaid other pair of contact elements.

RALPH G. MOODY.

